Local Option connections

Local Option uses the z/OS® operating system Program Call function for communication between IMS™ Connect and the IMS TM resource adapter that runs in WebSphere® Application Server for z/OS.

When your application is running on WebSphere Application Server for z/OS, the connection between the IMS TM resource adapter and IMS Connect can be either a TCP/IP connection or a Local Option connection. Local Option provides a more direct connection that does not go through TCP/IP. Instead, it uses z/OS Program Call services for cross-memory communication between the IMS TM resource adapter running in WebSphere Application Server for z/OS and IMS Connect running in its own address space, if both WebSphere Application Server and IMS Connect are running in the same z/OS image.

Important: The Local Option protocol is no longer enhanced, and does not provide the enhancements that are available in the z/OS support for TCP/IP. Choose Local Option only if you must use the thread identify and local Recovery Resource Services (RRS) two-phase commit feature. All new features in IMS TM Resource Adapter require TCP/IP connections.

Like TCP/IP connections, Local Option connections to IMS Connect are associated with an identifer called the client ID. IMS Connect ensures the uniqueness of these client IDs for all Local Option connections that it allows to be connected to it.

Unlike TCP/IP, which has two types of managed connections, shareable persistent and dedicated persistent, only shareable persistent socket connections are supported for managed Local Option connections to IMS Connect.

Restriction: Alternate client ID is not supported with Local Option.